The main objective of the proposed experiments is to delineate the critical neural substrates involved in specific systems such as cue-access, short and long term memory associated with the act of memory. It is believed that this objective can best be realized with the use of localized electrical brain stimulation. It is hoped that within the limits of problems associated with interpretation of the exact neuroanatomical system(s) affected by electrical brain stimulation and the temporal separation of a variety of psychological processes, it will be possible to delineate neural regions that have their maximal involvement in storage or retrieval phases of different systems associated with information processing. The first two experiments endeavor to test the role of the midbrain reticular formation (MRF) in the modulation of short-term memory and the hippocampus in the modulation of long-term memory in an appetitive and habituation learning situation. The third experiment attempts to delineate the contribution of the centrum-medianum parafascicularis complex in short and long term processing of aversive information. Experiments 4 and 5 represent an attempt to clarify further the role of the hippo-campus and MRF in retrieval of previously learned information. It is hoped to differentiate the role of various structures including the hippocampus and MRF in control of cue-access versus short and long term readout components of the retrieval process. Experiments 6 and 7 are designed to delineate possible transmitter charges (e.g. cholinergic) associated with brain stimulation (e.g. amygdala) and subsequent disruptive or facilitative effects upon mnemonic processes associated with affective information.